drm/i915: Streamline eDP handling in icl_combo_phy_aux_power_well_enable()

drm/i915: Streamline eDP handling in icl_combo_phy_aux_power_well_enable()

Drop the pointless phy/port detour from the eDP handling
in icl_combo_phy_aux_power_well_enable(). We can just directly
consult the dig_port and determine whether it's eDP or not.

This also removes the assumption that port==phy, although that is
always trued on ICL, so it wasn't really doing any harm.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229200357.7969-4-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>